U.S. patent application number 15/420914 was filed with the patent office on 2018-04-26 for crash detection circuit for the detection of a crash of a vehicle.
The applicant listed for this patent is Samsung SDI Co., Ltd.. Invention is credited to Maximilian Hofer, Thomas Korherr.
Application Number | 20180111572 15/420914 |
Document ID | / |
Family ID | 57354096 |
Filed Date | 2018-04-26 |
United States Patent
Application |
20180111572 |
Kind Code |
A1 |
Hofer; Maximilian ; et
al. |
April 26, 2018 |
CRASH DETECTION CIRCUIT FOR THE DETECTION OF A CRASH OF A
VEHICLE
Abstract
Embodiments of the present invention provide a crash detection
circuit for detecting a crash of a vehicle and including a
transformer including a first inductor as a part of a crash signal
generation circuit, and a second inductor as a part of a crash
signal evaluation circuit, and galvanically isolated from the first
inductor, a first comparator including an output, an inverting
input coupled to a first terminal of the second inductor, and a
non-inverting input electrically coupled to a second terminal of
the second inductor, and a window comparator including a first
input terminal electrically connected to the output of the first
comparator for an input voltage to be evaluated, and two second
input terminals for receiving reference voltages.
Inventors: |
Hofer; Maximilian;
(Hartberg, AT) ; Korherr; Thomas; (Hartberg,
AT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung SDI Co., Ltd. |
Yongin-si |
|
KR |
|
|
Family ID: |
57354096 |
Appl. No.: |
15/420914 |
Filed: |
January 31, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01D 5/20 20130101; G01D
5/145 20130101; B60R 16/02 20130101; G01R 27/2611 20130101; G01D
5/24466 20130101; G01D 5/2013 20130101; G01D 5/14 20130101 |
International
Class: |
B60R 16/02 20060101
B60R016/02; G01R 27/26 20060101 G01R027/26 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 26, 2016 |
EP |
16195835.0 |
Claims
1. A crash detection circuit for detecting a crash of a vehicle and
comprising: a transformer comprising: a first inductor as a part of
a crash signal generation circuit; and a second inductor as a part
of a crash signal evaluation circuit, and galvanically isolated
from the first inductor; a first comparator comprising: an output;
an inverting input coupled to a first terminal of the second
inductor; and a non-inverting input electrically coupled to a
second terminal of the second inductor; and a window comparator
comprising: a first input terminal electrically connected to the
output of the first comparator for an input voltage to be
evaluated; and two second input terminals for receiving reference
voltages.
2. The crash detection circuit of claim 1, further comprising a
voltage divider circuit comprising at least two resistors connected
in series, wherein a first terminal of one of the at least two
resistors is electrically connected to the non-inverting input of
the first comparator.
3. The crash detection circuit of claim 2, wherein a second
terminal of the one of the at least two resistors is electrically
connected to a first of the two second input terminals of the
window comparator, and wherein a third terminal of one of the at
least two resistors is electrically connected to a second of the
two second input terminals of the window comparator.
4. The crash detection circuit of claim 2, wherein the at least two
resistors comprise four series-connected resistors, wherein the
first terminal that is connected to the non-inverting input
electrically connects two inner resistors of the four
series-connected resistors.
5. The crash detection circuit of claim 4, wherein a first of the
two second input terminals of the window comparator is electrically
connected to a terminal of a first resistor of the four
series-connected resistors that is electrically connected to a
second resistor of the four series-connected resistors.
6. The crash detection circuit of claim 5, wherein a second of the
two second input terminals of the window comparator is electrically
connected to a terminal of a third resistor of the four
series-connected resistors that is electrically connected to a
fourth resistor of the four series-connected resistors.
7. The crash detection circuit of claim 4, wherein a terminal of a
first resistor of the four series-connected resistors that is not
connected to a second resistor of the four series-connected
resistors is electrically connected to a first voltage potential,
and wherein a terminal of a fourth resistor of the four
series-connected resistors that is not connected to a third
resistor of the four series-connected resistors is electrically
connected to a second voltage potential that is less than the first
voltage potential.
8. The crash detection circuit of claim 6, wherein the first of the
two second input terminals of the window comparator comprises an
inverting input of the window comparator, and wherein the second of
the two second input terminals of the window comparator comprises a
non-inverting input of the window comparator.
9. The crash detection circuit of claim 1, wherein the first
comparator comprises an operational amplifier.
10. The crash detection circuit of claim 1, further comprising a
parallel circuit comprising a resistor and a capacitor, wherein the
output of the first comparator is electrically connected to a first
terminal of the parallel circuit, and wherein a second terminal of
the parallel circuit is electrically connected to the inverting
input of the first comparator.
11. The crash detection circuit of claim 1, further comprising an
additional resistor between the inverting input of the first
comparator and the second inductor.
12. The crash detection circuit of claim 1, wherein the transformer
comprises a current transformer.
13. The crash detection circuit of claim 1, wherein the transformer
comprises a voltage transformer.
14. The crash detection circuit of claim 13, further comprising at
least one resistor is connected in series and/or in parallel to the
first inductor.
15. A vehicle including the crash detection circuit of claim 1.
Description
CROSS-REFERENCED TO RELATED APPLICATION
[0001] This patent application claims priority to, and the benefit
of, European Patent Application No. 16195835.0, filed on Oct. 26,
2016, in the European Patent Office, the content of which is
incorporated in its entirety herein by reference.
FIELD
[0002] Embodiments of the present invention relate to a crash
detection circuit for the detection of a crash of a vehicle.
TECHNOLOGICAL BACKGROUND
[0003] In crash detection circuits used for the detection of a
crash of a vehicle, optocoupler units are often arranged between a
crash signal generation circuit and a crash signal evaluation
circuit. The aforementioned optocoupler units serve to galvanically
isolate the crash signal generation circuit of the vehicle from the
electronics of the crash signal evaluation circuit of the vehicle.
However, such approaches for crash detection, which are based on
optocoupler units, are often relatively expensive, lack sufficient
robustness, have a relatively short lifetime, and do not allow for
transmittance of differentiated (e.g., positive and negative)
signals, as signaling between the crash signal generation circuit
and the crash signal evaluation circuit is solely performed via
light pulses.
[0004] A crash detection circuit of the state of the art may
suitably fulfill a plurality of conditions. According to a first
condition (e.g., according to a so called no-fire condition), the
crash detection circuit shall not detect a crash when a current in
the crash signal generation circuit is smaller than or equal to
about 0.4 A, and when a current impulse given in the crash signal
generation circuit is less than or equal to about 5 A and has a
duration that is less than or equal to about 4 .mu.s.
[0005] According to a second condition (e.g., according to a so
called fire condition), the crash detection circuit shall detect a
crash when a current in the crash signal generation circuit is
greater than or equal to about 1.75 A and less than or equal to
about 40 A for a maximum duration of about 0.5 ms in an operating
temperature range and when, for a duration that is less than or
equal to 2 ms, a current given in the crash signal generation
circuit is greater than or equal to about 1.2 A and has a duration
that is less than or equal to about 4 .mu.s.
[0006] In FIG. 1, the fire condition and the non-fire condition are
illustrated in a coordinate system. The ordinate (e.g., the y-axis)
of the coordinate system shows the current given within the crash
signal generation circuit, and the abscissa (e.g., the x-axis) of
the coordinate system shows the duration for which the respective
current is given within the crash signal generation circuit. In
FIG. 1, the dark areas illustrate an area in which the fire
condition is fulfilled, and the bright areas illustrate an area in
which the non-fire condition is fulfilled.
SUMMARY
[0007] One or more of the drawbacks of the prior art could be
avoided or at least reduced by means of embodiments of the present
invention.
[0008] A crash detection circuit is provided for the detection of a
crash of a vehicle. The crash detection circuit includes
[0009] An aspect of such a crash detection circuit is that it is
less expensive than, and has a higher robustness than, alternative
solutions of the state of the art (e.g. solutions using optocoupler
units). Furthermore, such crash detection circuits have a longer
lifetime, as more robust components come into use and are adapted
to transmit positive and negative signals.
[0010] Furthermore, the window comparator may further include an
output for a crash signal evaluation signal.
[0011] The reference voltages inputted into the second input
terminals may define the size of the voltage window of the window
comparator.
[0012] The crash detection circuit may further include a voltage
divider circuit including at least two resistors connected in
series, wherein a terminal of one of the at least two resistors is
electrically connected to the non-inverting input of the first
comparator. The use of such a voltage divider circuit together with
the first comparator and the window comparator allows for the fire
condition and the non-fire condition to be implemented within the
crash detection circuit. In other words, the use of such a voltage
divider circuit together with the first comparator and the window
comparator allows for the crash detection circuit to output a
signal indicating the detection of a crash when the fire condition
is met, and to output a signal indicating that a crash was not
detected when the non-fire condition is met. For this purpose, the
values of the at least two resistors may be chosen such that the
crash detection circuit is adapted to continuously control whether
the fire condition or the non-fire condition is met.
[0013] Moreover, another terminal of one of the at least two
resistors may be electrically connected to one of the two second
input terminals of the window comparator, and another terminal of
one of the at least two resistors may be electrically connected to
the other one of the two second input terminals of the window
comparator. In such an embodiment, the voltage window of the window
comparator is defined by constant reference voltages provided by
the voltage divider circuit, which allows for an efficient design
of the crash detection circuit, as the resistors of the voltage
divider circuit are used for a plurality of purposes.
[0014] The voltage divider circuit may include four
series-connected resistors, wherein the non-inverting input of the
first comparator is electrically connected to a terminal of one of
the four resistors, wherein the aforementioned terminal
electrically connects the second and the third resistors as counted
from one of the outermost resistors of the four series-connected
resistors. In such an embodiment, the threshold voltages or
reference voltages defining the voltage window of the window
comparator can be chosen in a more precise manner, as more
resistors allow for a division of the voltage supplied to the
voltage divider circuit into smaller fractions. All resistors of
the voltage divider circuit may have the same value, dividing the
voltage supplied to the voltage divider circuit into equal
fractions. In such an embodiment, a potential that is equal to half
the voltage supplied to the voltage divider circuit is supplied to
the non-inverting input of the first comparator. The voltage
divider circuit may include four series-connected resistors,
wherein the non-inverting input of the first comparator is
electrically connected to a terminal of one of the four resistors,
wherein the aforementioned terminal electrically connects the first
and the second resistor or the third and the fourth resistor as
counted from one of the outermost resistors of the four
series-connected resistors.
[0015] In an embodiment, one of the two second input terminals of
the window comparator is electrically connected to a terminal of
the first resistor, wherein the aforementioned terminal
electrically connects the first resistor with the second resistor.
The other one of the two second input terminals of the window
comparator is electrically connected to a terminal of the third
resistor, wherein the aforementioned terminal electrically connects
the third resistor with the fourth resistor. In such an embodiment,
the size of the voltage window of the window comparator is defined
by the voltage that drops at the series connection of the second
and third resistors. With such a realization, a crash detection
circuit is provided that includes a cost-efficient design allowing
for a reduction of components that come to use when compared to
alternative realizations known in the state of the art.
[0016] In an embodiment, the terminal of the first resistor that is
not connected to the second resistor is electrically connected to a
first voltage potential, and the terminal of the fourth resistor
that is not connected to the third resistor is electrically
connected to a second voltage potential, the first voltage
potential being greater than the second voltage potential. The
terminal of the first resistor that is not connected to the second
resistor is electrically connected to a first voltage potential,
which may be equal to about 5V. Furthermore, the terminal of the
fourth resistor that is not connected to the third resistor is
electrically connected to a second voltage potential, which may be
equal to the GND potential.
[0017] The second input terminal of the window comparator that is
electrically connected to a terminal of the first resistor is an
inverting input of the window comparator, and the second input
terminal of the window comparator that is electrically connected to
a terminal of the third resistor is a non-inverting input of the
window comparator. In such a realization, the potential supplied to
the inverting input of the window comparator denotes an upper
border of the voltage window of the window comparator. Furthermore,
the potential supplied to the non-inverting input of the window
comparator denotes a lower border of the voltage window of the
window comparator. In such an embodiment, the voltage at the output
of the window comparator depends on the result of a comparison of
the output voltage at the output of the first comparator with the
voltages being supplied to the second input terminals of the second
inductor, and thus being supplied to the upper and lower border of
the voltage window of the window comparator. In other words, the
window comparator compares the output voltage of the first
comparator to the reference voltages inputted into the second input
terminals of the window comparator. The window comparator outputs a
low signal when the output voltage of the first comparator falls
into the voltage window of the window comparator. Furthermore, the
window comparator outputs a high signal when the output voltage of
the first comparator falls out of the voltage window of the window
comparator.
[0018] In an embodiment, the first comparator is an operational
amplifier. Operational amplifiers have a low voltage offset, and
are generally very precise amplifiers.
[0019] The crash detection circuit may further include a parallel
circuit of a resistor and a capacitor, wherein the output of the
first comparator is electrically connected to a first terminal of
the parallel circuit, and wherein a second terminal of the parallel
circuit is electrically connected to the inverting input of the
first comparator. Such a parallel circuit in the feedback
connection of the first comparator adapts and adjusts the time
constant of the first comparator, allowing for the aforementioned
implementation of the fire condition and the non-fire
condition.
[0020] A resistor is connected in series to the first inductor. In
such an embodiment, the resistance of the input clamps of the crash
signal generation circuit is adapted.
[0021] In an embodiment, an additional resistor is arranged within
the electrical connection between the inverting input of the first
comparator and the terminal of the second inductor. Also this
resistor is used to precisely adjust the time constant of the first
comparator.
[0022] The transformer is a current transformer. In such an
embodiment, the crash detection circuit is usable with existing,
current generation sources present in vehicles, wherein such
current generation sources are adapted to generate a current in
case of a crash. The current generation source, for example, can be
a current source that is the emulation of a crash signal according
to a standard of a vehicle manufacturer.
[0023] In an alternative embodiment, the transformer is a voltage
transformer. In such an embodiment, the crash detection circuit is
usable with existing voltage sources present in vehicles, wherein
such voltage sources are adapted to generate a voltage in case of a
crash. The voltage source, for example, can be a voltage source
that is the emulation of a crash signal according to a standard of
a vehicle manufacturer.
[0024] At least one resistor is connected in series and/or in
parallel to the first inductor. Such an embodiment is especially
suited when the transformer is a voltage transformer. In such an
embodiment, the at least one resistor may be used to limit the
voltage supplied to the first inductor of the transformer.
[0025] Moreover, a vehicle including a crash detection circuit
according to embodiments of the invention is provided. In such an
embodiment, the crash detection of the vehicle is improved for the
aforementioned reasons.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Features will become apparent to those of ordinary skill in
the art by describing in detail embodiments of the present
invention with reference to the attached drawings, in which:
[0027] FIG. 1 shows a coordinate system with areas therein
illustrating the fire condition and the non-fire condition;
[0028] FIG. 2 illustrates a first embodiment of a crash detection
circuit;
[0029] FIG. 3 illustrates a second embodiment of a crash detection
circuit with a current transformer;
[0030] FIG. 4 illustrates a third embodiment of a crash detection
circuit with a voltage transformer, and
[0031] FIG. 5 illustrates a simulation using the second embodiment
of a crash detection circuit.
DETAILED DESCRIPTION
[0032] Features of the inventive concept and methods of
accomplishing the same may be understood more readily by reference
to the following detailed description of embodiments and the
accompanying drawings. Hereinafter, example embodiments will be
described in more detail with reference to the accompanying
drawings, in which like reference numbers refer to like elements
throughout. The present invention, however, may be embodied in
various different forms, and should not be construed as being
limited to only the illustrated embodiments herein. Rather, these
embodiments are provided as examples so that this disclosure will
be thorough and complete, and will fully convey the aspects and
features of the present invention to those skilled in the art.
Accordingly, processes, elements, and techniques that are not
necessary to those having ordinary skill in the art for a complete
understanding of the aspects and features of the present invention
may not be described. Unless otherwise noted, like reference
numerals denote like elements throughout the attached drawings and
the written description, and thus, descriptions thereof will not be
repeated. In the drawings, the relative sizes of elements, layers,
and regions may be exaggerated for clarity.
[0033] It will be understood that, although the terms "first,"
"second," "third," etc., may be used herein to describe various
elements, components, regions, layers and/or sections, these
elements, components, regions, layers and/or sections should not be
limited by these terms. These terms are used to distinguish one
element, component, region, layer or section from another element,
component, region, layer or section. Thus, a first element,
component, region, layer or section described below could be termed
a second element, component, region, layer or section, without
departing from the spirit and scope of the present invention.
[0034] Spatially relative terms, such as "beneath," "below,"
"lower," "under," "above," "upper," and the like, may be used
herein for ease of explanation to describe one element or feature's
relationship to another element(s) or feature(s) as illustrated in
the figures. It will be understood that the spatially relative
terms are intended to encompass different orientations of the
device in use or in operation, in addition to the orientation
depicted in the figures. For example, if the device in the figures
is turned over, elements described as "below" or "beneath" or
"under" other elements or features would then be oriented "above"
the other elements or features. Thus, the example terms "below" and
"under" can encompass both an orientation of above and below. The
device may be otherwise oriented (e.g., rotated 90 degrees or at
other orientations) and the spatially relative descriptors used
herein should be interpreted accordingly.
[0035] It will be understood that when an element, layer, region,
or component is referred to as being "on," "connected to," or
"coupled to" another element, layer, region, or component, it can
be directly on, connected to, or coupled to the other element,
layer, region, or component, or one or more intervening elements,
layers, regions, or components may be present. In addition, it will
also be understood that when an element or layer is referred to as
being "between" two elements or layers, it can be the only element
or layer between the two elements or layers, or one or more
intervening elements or layers may also be present.
[0036] In the following examples, the x-axis, the y-axis and the
z-axis are not limited to three axes of a rectangular coordinate
system, and may be interpreted in a broader sense. For example, the
x-axis, the y-axis, and the z-axis may be perpendicular to one
another, or may represent different directions that are not
perpendicular to one another.
[0037] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the present invention. As used herein, the singular forms "a" and
"an" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises," "comprising," "includes," and
"including," when used in this specification, specify the presence
of the stated features, integers, steps, operations, elements,
and/or components, but do not preclude the presence or addition of
one or more other features, integers, steps, operations, elements,
components, and/or groups thereof. As used herein, the term
"and/or" includes any and all combinations of one or more of the
associated listed items. Expressions such as "at least one of,"
when preceding a list of elements, modify the entire list of
elements and do not modify the individual elements of the list.
[0038] As used herein, the term "substantially," "about," and
similar terms are used as terms of approximation and not as terms
of degree, and are intended to account for the inherent deviations
in measured or calculated values that would be recognized by those
of ordinary skill in the art. Further, if the term "substantially"
is used in combination with a feature that could be expressed using
a numeric value, the term "substantially" denotes a range of +/-5%
of the value centered on the value. Further, the use of "may" when
describing embodiments of the present invention refers to "one or
more embodiments of the present invention." As used herein, the
terms "use," "using," and "used" may be considered synonymous with
the terms "utilize," "utilizing," and "utilized," respectively.
Also, the term "exemplary" is intended to refer to an example or
illustration.
[0039] When a certain embodiment may be implemented differently, a
specific process order may be performed differently from the
described order. For example, two consecutively described processes
may be performed substantially at the same time or performed in an
order opposite to the described order.
[0040] The electronic or electric devices and/or any other relevant
devices or components according to embodiments of the present
invention described herein may be implemented utilizing any
suitable hardware, firmware (e.g. an application-specific
integrated circuit), software, or a combination of software,
firmware, and hardware. For example, the various components of
these devices may be formed on one integrated circuit (IC) chip or
on separate IC chips. Further, the various components of these
devices may be implemented on a flexible printed circuit film, a
tape carrier package (TCP), a printed circuit board (PCB), or
formed on one substrate. Further, the various components of these
devices may be a process or thread, running on one or more
processors, in one or more computing devices, executing computer
program instructions and interacting with other system components
for performing the various functionalities described herein. The
computer program instructions are stored in a memory which may be
implemented in a computing device using a standard memory device,
such as, for example, a random access memory (RAM). The computer
program instructions may also be stored in other non-transitory
computer readable media such as, for example, a CD-ROM, flash
drive, or the like. Also, a person of skill in the art should
recognize that the functionality of various computing devices may
be combined or integrated into a single computing device, or the
functionality of a particular computing device may be distributed
across one or more other computing devices without departing from
the spirit and scope of the exemplary embodiments of the present
invention.
[0041] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which the present
invention belongs. It will be further understood that terms, such
as those defined in commonly used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and/or the present
specification, and should not be interpreted in an idealized or
overly formal sense, unless expressly so defined herein.
[0042] FIG. 2 illustrates a first embodiment of a crash detection
circuit 200. In this first embodiment, the crash detection circuit
200 may be implemented into a vehicle, and adapted to detect a
crash of the vehicle. The crash detection circuit 200 substantially
comprises two sub-circuits that are galvanically isolated from each
other. The first sub-circuit is a crash signal generation circuit
180 that is adapted to generate a crash signal. The crash signal
can be represented by a current or by a voltage that can be
generated by a current source or a voltage source, respectively.
The second sub-circuit is a crash signal evaluation circuit 170
that is adapted to evaluate the signal generated by the crash
signal generation circuit 180.
[0043] The crash detection circuit 200 comprises a transformer 90
that comprises a first inductor 91 forming a part of the crash
signal generation circuit 180, and a second inductor 92 that forms
a part of the crash signal evaluation circuit 170. The first and
the second inductors 91 and 92 are galvanically isolated from and
physically separated from each other. The crash detection circuit
200 further comprises a first comparator 80 that comprises an
output 85, an inverting input 81 and a non-inverting input 82, each
input 81 and 82 being respectively electrically coupled to one of
the terminals of the second inductor 92 of the transformer 90. In
other words, the inverting input 81 of the first comparator 80 is
electrically connected to a first terminal of the second inductor
92, and the non-inverting input 82 is electrically connected to a
second terminal of the second inductor 92.
[0044] Furthermore, the crash detection circuit 200 comprises a
window comparator 70. The window comparator 70 comprises a first
input terminal 75 for an input voltage to be evaluated, and
comprises two second input terminals 71 and 72 for reference
voltages U.sub.ref1 and U.sub.ref2. The reference voltages
U.sub.ref1 and U.sub.ref2 define the size of the voltage window of
the window comparator 70, and are supplied to the two second input
terminals 71 and 72. The first reference voltage U.sub.ref1 is
supplied to the first of the two second input terminals 71, and
defines an upper border of the voltage window of the window
comparator 70. The second reference voltage U.sub.ref2 is supplied
to the second of the two second input terminals 72, and defines a
lower border of the voltage window of the window comparator 70. In
this first embodiment, the reference voltages U.sub.ref1 and
U.sub.ref2 are constant, and are supplied by a component of the
crash signal evaluation circuit 170. Moreover, in this first
embodiment, the mean value U.sub.mean of the reference voltages
U.sub.ref1 and U.sub.ref2 is supplied to the non-inverting input 82
of the first comparator 80, wherein the mean value U.sub.mean is
equal to (U.sub.ref1+U.sub.ref2)/2. In this first embodiment, the
mean value U.sub.mean is supplied to the non-inverting input 82 of
the first comparator 80 via the aforementioned component of the
crash signal evaluation circuit 170. However, the mean value
U.sub.mean can also be provided to the non-inverting input 82 via
another component.
[0045] The output 85 of the first comparator 80 is electrically
connected to the first input terminal 75 of the window comparator
70. Thus, the signal outputted by the output 85 of the first
comparator 80 is compared to the reference voltages U.sub.ref1 and
U.sub.ref2. In this first embodiment, the reference voltages are
chosen such that the crash signal evaluation circuit 170
continuously evaluates whether the fire condition or the non-fire
condition, as shown in the coordinate system of FIG. 1, is met.
Thus, the window comparator 70 outputs a corresponding signal via
its output 79 when the fire condition is met and a crash has been
successfully detected.
[0046] In FIG. 3, a second embodiment of a crash detection circuit
200 with a current transformer 90 is shown. Also in this second
embodiment, the crash detection circuit 200 comprises a crash
signal generation circuit 180 and a crash signal evaluation circuit
170. The crash signal generation circuit 180 comprises a current
source 181 for the generation of a current corresponding to a crash
signal. In FIG. 3, the current source 181 is shown as a single
component. However, in other embodiments, the current within the
crash signal generation circuit 180 can be generated via a
plurality of components. Furthermore, the crash detection circuit
200 comprises a transformer 90, which is realized as a current
transformer 90 in this second embodiment. Via the first inductor 91
of the current transformer 90, a current can be induced in the
second inductor 92 that forms a part of the crash signal evaluation
circuit 170. In this second embodiment, the first comparator 80 is
realized as an operational amplifier, wherein the inverting input
81 of the operational amplifier is electrically connected to a
first terminal of the second inductor 92, and wherein the
non-inverting input 82 of the operational amplifier is electrically
connected to a second terminal of the second inductor 92. A first
power supply terminal 84 of the operational amplifier is
electrically connected to a potential of about 5V, wherein the
other power supply terminal 86 of the operational amplifier is
electrically connected to a GND potential.
[0047] In this second embodiment, the crash signal evaluation
circuit 170 further comprises a voltage divider circuit 160 that
comprises four series-connected resistors 61, 62, 63, and 64. In
other words, the voltage divider circuit 160 comprises a first
terminal 161 electrically connected to a first resistor 61. This
first resistor 61 is electrically connected to a second resistor
62, which is electrically connected to a third resistor 63. This
third resistor 63 is electrically connected to a fourth resistor
64, which is electrically connected to a second terminal 162 of the
voltage divider circuit 160. In this second embodiment, the first,
second, third, and fourth resistor 61, 62, 63, and 64 have an
identical value. However, in other embodiments, the values of the
first, second, third, and fourth resistor 61, 62, 63, and 64 may
differ from one another. Moreover, in other embodiments, the
voltage divider circuit 160 can comprise three resistors, or can
comprise more than four resistors.
[0048] Furthermore, in this second embodiment, the first terminal
161 of the voltage divider circuit 160 is electrically connected to
a potential of, for example, about 5V, wherein the second terminal
162 of the voltage divider circuit 160 is electrically connected
to, for example, the GND potential. However, the first and second
terminals 161 and 162 of the voltage divider circuit 160 can also
be connected to other potentials. In this second embodiment, the
non-inverting input 82 of the first comparator 80 is electrically
connected to a terminal of one of the four resistors 61, 62, 63,
and 64, wherein the aforementioned terminal electrically connects
the second and the third resistors 62 and 63, as counted from one
of the outermost resistors 61 and 64 of the four series-connected
resistors 61, 62, 63, and 64 (e.g., two inner resistors 62 and 63
of the four resistors 61, 62, 63, and 64). In other words, the
non-inverting input 82 of the first comparator 80 is directly
electrically connected to the terminals of the second and third
resistor 62 and 63, that in this second embodiment have a potential
of, for example, about 2.5V.
[0049] In this second embodiment, one of the two second input
terminals 71 of the window comparator 70 is electrically connected
to a terminal of the first resistor 61, wherein the aforementioned
terminal electrically connects the first resistor 61 with the
second resistor 62. In more detail, in this second embodiment, the
first of the two second input terminals 71 of the window comparator
70, which may be an inverting input terminal of the window
comparator 70, is directly electrically connected to the terminals
of the first and second resistor 61 and 62. Moreover, in this
second embodiment, the second of the two second input terminals 72
of the window comparator 70, which may be a non-inverting input
terminal of the window comparator 70, is directly electrically
connected to the terminal of the third resistor 63 that is directly
connected to the fourth resistor 64. In more detail, in this second
embodiment, the second of the two second input terminals 72 of the
window comparator 70, which may be a non-inverting input terminal
of the window comparator 70, is directly electrically connected to
the terminals of the third and fourth resistor 63 and 64.
[0050] In this second embodiment, the voltage drop across the
second and third resistors 62 and 63 determines the size of the
voltage window of the window comparator 70 that has a span of, for
example, about 2.5V.
[0051] The output 85 of the first comparator 80 is electrically
connected to the first input terminal 75 of the window comparator
70. The window comparator 70 comprises two further comparators 70-1
and 70-2 that also can be operational amplifiers. However, also
other and/or additional comparators can come to use, the
other/additional comparators together forming a window comparator
70.
[0052] The crash detection circuit 200 further comprises a parallel
circuit 50 of a resistor 51 and a capacitor 52, wherein the output
85 of the first comparator 80 is electrically connected to a first
terminal of the parallel circuit 50, and wherein a second terminal
of the parallel circuit 50 is electrically connected to the
inverting input 81 of the first comparator 80. In other words, the
parallel circuit 50 is arranged within the feedback circuit of the
first comparator 80. Moreover, an additional resistor 55 is
arranged within the electrical connection between the inverting
input 81 of the first comparator 80 and the terminal of the second
inductor 92. Via the parallel circuit 50 and the additional
resistor 55, the time constant of the operational amplifier may be
adjusted according to the non-fire condition and the fire condition
as illustrated in FIG. 1.
[0053] Via the output 79 of the window comparator 70, the crash
signal evaluation circuit 170 outputs an output signal that is
determined according to the evaluation.
[0054] FIG. 4 illustrates a third embodiment of a crash detection
circuit 200 with a voltage transformer 90. The crash detection
circuit 200 shown in FIG. 4 is substantially identical to the crash
detection circuit 200 shown in FIG. 3. However, as in this third
embodiment, a voltage transformer 90 comes to use, and the crash
signal generation circuit 180 is therefore adapted. Thus, in this
third embodiment, two resistors 58 are connected in series to the
first inductor 91 of the voltage transformer 90, wherein an
additional resistor 59 is connected in parallel to the first
inductor 91 of the voltage transformer 90.
[0055] In FIG. 5, a simulation is illustrated using the second
embodiment of a crash detection circuit 200. In more detail, two
diagrams are shown in FIG. 5. The upper diagram shows different
crash pulses that are given as an input for the crash detection
circuit 200 within the crash signal generation circuit 180. The
lower diagram shows the evaluation of the crash detection circuit
200 at its output 79. It can be seen from FIG. 5 that the crash
pulses denoted A have a duration that is too short to fulfill the
fire condition (see FIG. 1), while the crash pulses denoted B have
a current amplitude that is too low to fulfill the fire condition
(see FIG. 1), as no output signal is generated to be outputted at
the output 79 of the crash detection circuit 200.
[0056] However, this is not the case for the crash pulses C and D,
which fulfill the fire condition (see FIG. 1), as pulses are
outputted at the output 79 of the crash detection circuit 200, the
pulses being visible within the lower diagram.
* * * * *